fix PHP 7 compatibility

[remicollet]

Probably could be improved, but initial PHP 7 support seems OK.

 =====================================================================
 PHP         : /opt/remi/php70/root/usr/bin/php 
 PHP_SAPI    : cli
 PHP_VERSION : 7.0.0-dev
 ZEND_VERSION: 3.0.0-dev
 PHP_OS      : Linux - Linux schrodingerscat.famillecollet.com 3.19.3-200.fc21.x86_64 #1 SMP Thu      Mar 26 21:39:42 UTC 2015 x86_64
 INI actual  : /work/GIT/libsodium-php/tmp-php.ini
 More .INIs  :  
 CWD         : /work/GIT/libsodium-php
 Extra dirs  : 
 VALGRIND    : Not used
 =====================================================================
 TIME START 2015-04-02 16:40:24
 =====================================================================
 PASS Check for libsodium AEAD [tests/crypto_aead.phpt] 
 PASS Check for libsodium box [tests/crypto_box.phpt] 
 PASS Check for libsodium generichash [tests/crypto_generichash.phpt] 
 PASS Check for libsodium bin2hex [tests/crypto_hex.phpt] 
 PASS Check for libsodium secretbox [tests/crypto_secretbox.phpt] 
 PASS Check for libsodium shorthash [tests/crypto_shorthash.phpt] 
 PASS Check for libsodium ed25519 signatures [tests/crypto_sign.phpt] 
 PASS Check for libsodium stream [tests/crypto_stream.phpt] 
 PASS Check for libsodium presence [tests/installed.phpt] 
 PASS Check for libsodium utils [tests/pwhash.phpt] 
 PASS Check for libsodium randombytes [tests/randombytes.phpt] 
 PASS Check for libsodium utils [tests/utils.phpt] 
 PASS Check for libsodium version [tests/version.phpt] 
 =====================================================================
 TIME END 2015-04-02 16:40:24

[remicollet]

Notice, run-tests.php doesn't have to be in git, you can remove it and add it to .gitignore

[remicollet]

The main issue is that I haven't found a easy wait to create a STRING without copy...
Should use zend_string_allocate and then directly use the buffer. But seems difficult to use and keep PHP 5 compatiblity.

[remicollet]

Previous commit is an example about fixing this....
Seems really less legible.

[remicollet]

Any feedback on this PR ?

[jedisct1]

Hi Remi,

And thanks a lot for this!

A few comments, though.

Introducing strsize_t is great. However, if string sizes can be larger than INT_MAX, there are additional changes to make. There are quite a few checks specifically to avoid going beyond INT_MAX, even though the underlying API doesn't have this limitation.
If we can go up to SIZE_MAX or SSIZE_MAX, these checks should be adjusted accordingly. Or if we consider that INT_MAX is the maximum string length even on PHP7, additional checks on input arguments are required.

The double allocation is a bit annoying. And it renders sodium_memzero() moot since we can have a previous copy around. This can be fixed with a systematic sodium_memzero() call before the efree() call in your macro, but this is yet more overhead piling up.
Wondering if the #if PHP_MAJOR_VERSION < 7 couldn't be replaced by additional macros.

[remicollet]

Yes, this is a quick fix, and of course, I don't know enough of libsodium to do the perfect fix.

There is a difficult choice with zend_string,

• keep code compatible using a few macro (my preferred choice when possible)
• maintain 2 versions of the sources

I don't see simple way to use zend_string and get rid of #if PHP_MAJOR_VERSION < 7, or perhaps by providing a zend_string for PHP < 7

I think keeping INT_MAX is probably enought for a few years ;)

[remicollet]

What do you think of rev 5134347 ?

Code really looks like PHP 7 code, all managed by the compatibility layer.

[remicollet]

Waiting for your feedback before trying to remove all remaining call to _RETURN_STRINGL

[remicollet]

Rebased on 0.1.3

[jedisct1]

Finally merged, with minor changes.

Thanks a ton for your help, Remy!